1. Field of the Invention
In general, the present invention relates to dispensing pumps that are used to draw liquid material out of a container. More particularly, the present invention relates to dispensers that are used to draw material out of an inverted container.
2. Prior Art Description
Commercial products, such as shampoos, conditioners, skin moisturizers, honey, ketchup are a few examples of high-viscosity liquids that are packaged for retail sale. Such products are typically packaged for retail sale in either bottles or tubes.
The most common method of dispensing a high-viscosity liquid from a container is to provide the bottle or tube with a dispensing cap. A dispensing cap is a cap closure containing an orifice that can be selectively opened or closed. To dispense the high-viscosity material out of the container, the orifice in the cap is opened. The container is then squeezed to displace the high-viscosity material out of the container through the open orifice. If the container is nearly empty, the container is inverted so that the high-viscosity material slowly pools near the dispensing cap.
The problem associated with such dispensing systems is that the viscosity of the material may cause the material to flow very slowly. As such, the material may take a long time to flow to the dispensing cap when the container is inverted. Furthermore, the high viscosity of the material causes the material to cling to the walls of the container and resists movement toward the dispensing cap. As a result, some material always remains within the container that cannot be dispensed. This residual material is thrown away with the old container when a new full container is purchased.
Throwing away residual material in a container is of little concern when the material is inexpensive. However, there are many materials, such as skin care lotions, that can cost more than twenty dollars an ounce. With such high-priced materials, consumers expect to extract every drop of the material from its packaging container.
In the prior art, many highly viscous liquid products are packaged with pump dispensers to help draw material out of the confines of a container. For instance, most liquid soap dispensers contain small manual pumps to draw the soap up out of the container. In such prior art containers, the pump is located at the top of the container. A tube leads into the container and draws material from the bottom of the container. Such prior art dispensing systems are exemplified by U.S. Pat. No. 3,966,095 to Chappell, entitled Horizontally Operated Pump-Type Dispenser.
Pump dispensers that use drawtubes have a problem similar to that of squeeze containers. The drawtube of a pump dispenser draws material only from one small point in the container. Consequently, a large volume of residual material may be left within a container that cannot be received by the drawtube.
The one sure way to draw most all residual material out of a container is to eliminate the drawtube by inverting the container and pumping material from the lowest point under the container. In this manner, gravity will bias all residual material toward the dispensing pump. The obvious problem with such systems is that the container of material must be mounted atop the dispensing pump. This recreates a top-heavy and unstable assembly. Furthermore, since the pump is located at the bottom of the system, access to the pump is blocked by the presence of the inverted container. As a result, inverted container pump dispensers have been limited to wall mounted units, such as is exemplified by U.S. Pat. No. 6,601,736 to Ophardt, entitled Liquid Dispenser For Dispensing Foam. It will be understood that for everyday applications, wall mounted dispenser systems are impractical.
A need therefore exists for a dispensing system that can draw the free-flowing contents and residual material out of many different types of prepackaged containers without requiring that the dispensing system be wall mounted or the dispensing point being difficult to access. This need is met by the present invention as described and claimed below.